Once you've verified on a breadboard that the functionality you want to build works it's time to move away from the breadboard and make a reliable prototype.
I showed you different tools for stripping cables and we talked about the difference between cable with a single core and several strands. Colors are up to you, really, but keep in mind that the standard is that black is minus/GND and red is plus.
Potentiometers are great gadgets for control. They come with a nut which makes it easy to mount them through a surface, and you can make your own knob to put on the shaft.
To avoid cables popping loose you can of course solder them to the components involved, but I also showed you the benefit of male and female headers. You can make your own plugs to stick into an arduino, certain sensors, or simply build your own extensions to make it easier to disassemble for travel and assemble again. Remember to use hot glue to further protect solderings in moving parts.
The halfway solution between breadboards and circuit boards. Simpler circuits can be done by just soldering cables between components, but once you've got some more complex connections you will want to use prototyping boards. They come in three versions where the holes are either not connected to each other, in threes or in complete lines. I've found that the kind where the holes connect in threes are most versatile and useful. You don't have to make EVERY connection yourself with a cable, but there's enough variation that you can build whatever you want. It takes a bit of practice to get acquainted with these, but once you do, you can build amazing things.
I showed you the simpler button, which needs a minor change in code, but apart from just being simpler also invites the possibility of making any two conductive things a possible button to trigger on.
I also showed you some photos of actual buttons that we have in the tower. There's a whole WORLD outside of 12mm black circle buttons.
I mentioned some sensors available to explore, pressure sensors (amount of pressure, or position) accelerometers, light, temperature, knock. All used the same way as the potentiometer.
There are also smaller Arduinos which you can use, and even smaller than that, the ATtiny which you can program almost the same way AND it runs off a button battery.